I think it would put Rey on an even footing with kylo on an emotion level, in the hanger scene you can have Kylo tell Rey “we are heirs of the darkside and we will take it’s throne” really lean in on the similarities between them -the “dyad”. this would make the ending far more impactfull (especially if we make ben live) as we have them both reject their innate darkness and begin a new future with the light- it rhymes.
I’d be careful to use the word “heir” in a Rey Nobody edit in that context.